1. Field of the Invention
The present invention relates to an apparatus and method for manufacturing a balloon catheter, and more particularly, to an apparatus and method for manufacturing a balloon catheter in which: a laser perforator and printer are separately provided above a T-shaped die of a primary tube extruder such that inflation apertures, each having a predetermined area and length, can be accurately and uniformly perforated through an elongated non-vulcanized lumen tube and tube cutting positions can be printed on the non-vulcanized tube without stopping a primary extrusion process; and a bond preventing agent layer is coated on an outer surface of the elongated lumen tube at balloon inflating portions prior to cutting the elongated lumen tube to facilitate the implementation of a secondary extrusion, whereby high productivity and minimized loss of material can be achieved.
2. Description of the Related Art
As known, a catheter, which is conventionally made of silicon, is a thin and long circular tube adapted to be inserted into the human body in order to drain a body fluid or to inject a therapeutic fluid. For instance, such a catheter may be used to drain urine. In this case, the catheter is inserted into the bladder through the urethra so as to drain urine collected in the bladder.
FIG. 1 is a sectional view illustrating a tip portion of a conventional balloon catheter.
As shown in FIG. 1, the conventional balloon catheter includes a lumen tube 13 formed with a partition 19 therein to define a primary lumen 12 and an inflation lumen 14, and a balloon layer 16 partially bonded to an outer surface of the lumen tube 13 to provide a balloon. The primary lumen 12 serves to drain urine introduced from the bladder through a urine drainage hole 17, whereas the inflation lumen 14 serves to inflate the balloon provided by the balloon layer 16. An inflation hole 15 is also formed at the lumen tube 13 in order to communicate the inflation lumen 14 with an interior space 16a of the balloon.
In order to manufacture the balloon catheter having the above mentioned configuration, an extrusion process is carried out to extrude an intermediate tube having the primary lumen 12 and inflation lumen 14. Thereafter, the extruded intermediate tube is primarily vulcanized, and then cut into tube pieces having a desired length, that is, lumen tubes 13.
Subsequently, the inflation hole 15 and urine drainage hole 17 are perforated through each lumen tube 13. A tip 11 is then formed at one end of each lumen tube 13. Thereafter, a balloon manufactured in a separate molding process is bonded, as the balloon layer 16, to the outer surface of each lumen tube 13 by an adhesive 18. Each lumen tube 13 is then subjected to an overcoating process to form an overcoat layer 20. The overcoating process is performed for the sake of removing any protrusions on the outer surface of each lumen tube 13.
In the above mentioned conventional balloon catheter, however, there is a problem in that it may cause a patient great pain during a surgical operation because its balloon-bonded portion has a diameter relatively larger than that of other portions. Furthermore, the bonded portions of the balloon may be separated. First of all, the conventional balloon catheter results in a complicated process and high manufacturing costs.
As a solution to eliminate the above mentioned problems of the conventional balloon catheter, another conventional catheter manufacturing method is disclosed in U.S. Pat. No. 5,137,671.
This method will be described hereinafter with reference to FIGS. 2A to 2E. First, a double lumen tube 100 is prepared, as shown in FIG. 2A. The double lumen tube 100 is formed with a first lumen 120 (a larger diameter fluid conduit lumen) and a second lumen 140 (a smaller diameter capillary lumen).
A capillary lumen access opening 160 is punched through the prepared lumen tube 100 at an intermediate portion of the lumen tube 100, that is, a balloon inflating portion, so that it communicates with the second lumen 140, as shown in FIG. 2B. The second lumen 140 is then filled with a polymeric filling material 180 such as silicon rubber between one end thereof (that is, the left end in FIG. 2B) and a point just before the capillary lumen access opening 160. A tip 200 is attached to one end of the lumen tube 100 corresponding to the end of the second lumen 140, so that both of the first and second lumens 120 and 140 are closed at one end thereof.
Subsequently, a portion of the lumen tube 100 extending from one end of the lumen tube 100 to the balloon inflating portion, that is, up to the line A-A in FIG. 2B, is dipped into a bond preventing agent solution (a liquid soap or petrolatum), and then dried, so that it is coated at an outer surface thereof with a solidified bond preventing agent layer 300. The bond preventing agent layer 300 fills the capillary lumen access opening 160 and a portion of the second lumen 140. Thus, the bond preventing agent layer 300 has a cross section as shown in FIG. 2B. That is, the portion of the second lumen 140 between the line A-A and the capillary lumen access opening 160 is filled with the bond preventing agent layer 300, and the outer surface portion of the lumen tube 100 between the line A-A and the end of the lumen tube 100 adjacent to the tip 200 is coated with the bond preventing agent layer 300, along with the tip 200, as shown in FIG. 2B.
Thereafter, a portion of the lumen tube 100 extending up to the line B-B in FIG. 2C, that is, just before the balloon inflating portion, is treated using a surface active agent, and then dipped into hot water or other hot aqueous solution several times, so as to remove the bond preventing agent layer 300 therefrom. Thus, the bond preventing agent layer 300 remains only at the balloon inflating portion of the lumen tube 100, as shown in FIG. 2C. A liquid-phase silicon is then coated over the entire outer surface of the lumen tube 100 to form a silicon layer 400, as shown in FIG. 2D. The silicon layer 400 may have a multi-layer structure including laminated layers 410 and 420.
Then, a solvent for melting and removing the bond preventing agent is injected into the second lumen 140 from the other end of the second lumen 140, so that the remaining bond preventing agent layer 300 filling and covering the balloon inflating portion is completely removed from the second lumen 140 of the lumen tube 100, thereby forming a balloon inflation cavity 440, as shown in FIG. 2E. Thus, a balloon catheter is obtained.
However, this balloon catheter manufacturing method has a problem in that it causes environmental pollution due to waste water produced during the procedure of dipping the lumen tube 100 into water several times in order to remove the bond preventing agent from the portion of the lumen tube 100 (between the line B-B and the tip-side end) other than the balloon inflating portion.
Furthermore, where the bond preventing agent is incompletely removed, the residue thereof is moved to the tip 200 when the balloon inflation cavity is inflated, thereby causing the overcoat layer to be stripped around the balloon inflating portion. As a result, the overcoat layer may be inflated around the balloon inflating portion.
Also, the above mentioned conventional balloon catheter manufacturing method still has the problem caused by the diameter of the balloon inflating portion being larger than that of other portions.
As another conventional example, there is a silicon rubber catheter disclosed in Japanese Utility Model No. 3015310 registered on Jun. 21, 1995.
In this catheter, a balloon is formed on the outer surface of a catheter body such that it is integral with the catheter body. The catheter body is formed using silicon rubber in accordance with a primary extrusion process so that it is defined with a fluid conduit lumen and a capillary lumen therein, and formed with a channel at the outer surface thereof. The catheter body is subjected to a vulcanization process, and then coated with a bond preventing agent at a balloon forming portion thereof. Thereafter, a balloon layer is laminated using silicon rubber over the outer surface of the catheter body in accordance with a secondary extrusion process, and then vulcanized. A tip is then formed at the catheter body. In this structure, the outer surface of the balloon layer is flush with the outer surface of the catheter body at the catheter body portion other than the balloon forming portion, so that there is no step formed at the outer surface of the catheter body. Accordingly, there is no resistance caused by steps, and no deformation in the outer surface of the balloon layer.
However, it is difficult to practically manufacture such a catheter, in which the balloon is integral with the catheter body.
This is because the silicon rubber layer coated in the secondary extrusion process may penetrate into the channel. Where the silicon rubber layer is coated without any penetration thereof into the channel, it is difficult to obtain a sufficient bonding force to the catheter body. In this case, the silicon rubber layer may be stripped even at a region other than the balloon forming portion. Furthermore, even if the secondary extrusion process is successfully accomplished with no stripping and penetration of the silicon rubber layer, it is very difficult to provide the inflated balloon with a symmetrical shape because the channel leaves a longitudinal mark at an inner surface of the balloon.
To solve the above mentioned problems, the applicant of the present invention filed a patent application entitled “METHOD FOR MAKING BALLOON CATHETER” on 2001. The filed patent was published as Patent Registration No. 10-0434720.
The method for making a balloon catheter disclosed in the Patent Registration No. 10-0434720 will be described with reference to FIGS. 3A to 3C. The disclosed method comprises the steps of: primarily extruding an elongated lumen tube provided with a fluid drainage lumen and an inflation lumen while having an outer diameter slightly smaller than that of a desired balloon catheter, vulcanizing the elongated lumen tube, and cutting the elongated lumen tube into unit lumen tubes respectively corresponding to the desired balloon catheter; fitting a support rod in the fluid drainage lumen of each unit lumen tube to extend up to a balloon forming region where a balloon is to be formed on the unit lumen tube, and perforating two inflation apertures having a small diameter through the unit lumen tube at the balloon forming region; coating a bond preventing agent on an outer surface of each unit lumen tube at the balloon forming region; removing the support rod from each unit lumen tube, connecting the unit lumen tubes in series by connectors, secondarily extruding a balloon tube on the connected unit lumen tubes, vulcanizing the balloon tube, and cutting a resulting tube structure obtained after the vulcanization of the balloon tube into tube pieces respectively corresponding to the unit lumen tubes; forming a tip at one end of each tube piece; and perforating a urine drainage hole through each tube piece.
The above mentioned method, however, has the following several problems Firstly, as shown in FIG. 3C, since it is necessary to reduce a thickness ta of the lumen tube as thin as possible in order to increase the size of the fluid drainage lumen 12 and inflation lumen 14 to the maximum extent, perforation of the inflation apertures is very difficult, and such a difficulty may result in deterioration of productivity and increased amount of poor products. Secondly, where the inflation apertures are manually perforated through the lumen tube by use of elongated tools having a rod shape, the lumen tube must be cut prior to perforating the inflation apertures, for the sake of handling convenience. In this case, the lumen tube must be cut such that each unit lumen tube has a length longer than a desired length of the balloon catheter in consideration of the following processes, and the unit lumen tube must be cut again to have an accurate length after a secondary extrusion process. Accordingly, loss of material and excessive waste of labor are inevitable. Thirdly, if the thickness ta of the lumen tube is excessively thin, the inflation apertures may be perforated to extend up to unintentional positions or the lumen tube may be unintentionally stretched rather than being perforated with the inflation apertures. However, thickening the lumen tube to some extent in order to prevent the above problems of the excessively thin thickness must worsen abrasion of a cutting blade. This may result in deterioration of productivity due to frequent exchange of blades. For these reasons, although it is well known that it is better to reduce the thickness of the lumen tube as thin as possible, there is a limit to practically reduce the thickness of the lumen tube.